Charging Behavior of Polyimide/Adhesive Components During Eclipse Events in Geostationary Environment

Abstract

This paper presents an experimental and numerical study carried out in the SIRENE irradiation test facility, installed at ONERA (Toulouse, France), on stacked polyimide/adhesive structures used on solar panels. This study aims at following the evolution of the charging potential built up at the surface of these structures during an eclipse event in geostationary orbit. The samples have therefore been irradiatedwith adistributed electron spectrum (from0 to 400 keV). During a first stage, the samples are submitted to light radiation at 293 K. In a second stage (eclipse phase), the electron irradiation is performed in darkness and with a decreasing temperature (down to 113 K). In a final stage (eclipse exit), the samples are submitted to light radiation with an increasing temperature (up to 293 K). We have been able to demonstrate that these solar structures are highly sensitive to temperature and light radiation since the volume conductivity of polyimide films and epoxy adhesives is submitted to noticeable variation with these operative parameters. The major conclusion is that this kind of polyimide/adhesive structure potentially used on solar panels may have to cope with elevated charging potential, which can be highly hazardous especially at the eclipse exit when the solar panel regains its power.